Growth and tropic movements of plants / by Sir Jagadis Chunder Bose.

  • Jagadish Chandra Bose
Date:
1929
Catalogue details

Licence: In copyright

Credit: Growth and tropic movements of plants / by Sir Jagadis Chunder Bose. Source: Wellcome Collection.

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    nearer the fulcrum. The Connector, which joins the first to the second lever, has to be flexible. For this I employed different devices, of which the following is simple and effective. The connection is made by a thin waxed string which has been previously kept stretched for several days by a weight. A moderate tension does not stretch the prepared string any further, nor is the string affected by any hygroscopic change. Fig. i . Compound lever of High Magnification Crescograph. p, plant attached to arm of lever, l ; i/, second lever with bent tip for tracing record ; w, w', balancing counterpoise ; each lever is carried by a fork ; the transverse fulcrum-bar of the lever ends in pin-points which rest in agate cups, one on each side of the fork. The attachment of the plant to the first lever may be to the short arm of the lever, in which case the growth- elongation is recorded as a down-curve. It is perhaps more natural to associate upward growth with an up-curve ; this may be secured by attaching the plant to the long arm of the lever (fig. i). The curvature in the record is slight, and is practically negligible in the middle portion of it.